Author: Vincent Diepeveen
Date: 15:51:46 04/18/01
Go up one level in this thread
On April 18, 2001 at 09:04:42, José Carlos wrote: >On April 18, 2001 at 05:25:52, Vincent Diepeveen wrote: > >>On April 17, 2001 at 16:07:35, José Carlos wrote: >> >>>On April 17, 2001 at 14:51:45, Gian-Carlo Pascutto wrote: >>> >>>>On April 17, 2001 at 13:30:22, Vincent Diepeveen wrote: >>>> >>>>>> Are you sure you spend most of your time in eval? My problem is inCheck() >>>>>>since ever. That's where my prog spends most of the time. >>>>>> The good thing is that, everytime I want to improve the speed of my >>>>>>program, I know exactly where to focus on :) >>>>>> I suggest you to profile your program to know exactly where the time is >>>>>>spend, although probably you've already done this. >>>>>> >>>>>> José C. >>>>> >>>>>How can this eat system time anyway? >>>> >>>>If you dont have any attack information available incheck can be >>>>costly. In Sjeng it topped the running profile a long time, though only >>>>with 15%-20% of the total time or so. >>>> >>>>I speeded my incheck/legal_move up greatly by looking at the move last >>>>played and figuring out if it could possibly have put the king in check. >>> >>> Exactly. That's what I'm doing right now. But actually my makemove() function >>>is about 5000 lines !!! And I still haven't remove half the inCheck() calls !! >>> This is driving me mad, since there're a lot of rare cases that you must take >>>into account. Really hard, but I hope it's worth the effort. >> >>what do you do in makemove? >> >>If you do next: >> >> if( possiblecheck[piece][fromfield][kingfield] >> && scanbetween(piece,fromfield,kingfield) ) > > I see. You have all that information stored in a table, so a lookup is enough. >But anyway, suppose you're already in check. Now you capture a pawn en passant. >Are you still in check after that? > You have to check if the captured pawn was checking your king. Depending on >whether that's true or false, you much check if both pawns disappearing open a >line for an enemy sliding piece towards your king. If all of that if false, you >still need to check if there was another piece cheking your king (it could be a >double check), etc... > I don't see how you know it so easily. well in diep this problem is of course never happening as i do attacktables incremental. if i wouldn't have attacktables incremental and i have a compile flag to switch'em off, then i simply capture the king from the board and return mate score if i capture the king. Just capture the king. Easy. Why call a function always if the few cases that escape attention hardly happen? I don't need to know that i'm in check at all. I just capture the king if i can get it. It's worth a bit more as capturing a queen of course, so sorting will quickly pick it out. You focussed perhaps too much on an exception which rarely happened? > José C. > >>i do not see how figuring out whether such a move is a check can cost >>more as say 1% system time even in a program getting half a million >>nodes a second at a PII450. >> >>Best regards, >>Vincent >> >>> José C. >>> >>>>You can apply a lot of tricks to make this very fast. >>>> >>>>Now it is way down on the profile (>3% or so), and my program became about >>>>6% faster. Now need to find a way to get SEE attack info quicker :) >>>> >>>>-- >>>>GCP
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